Patent · US Expired

Method for ASK demodulation, and ASK demodulator

US6307428A · kind A · utility

7Cited by

1References

6Claims

0Family size

Assignee

Infineon Technologies AG · DE

Inventors

Gerhard Nebel · Immenstadt im Allgäu, DE
Volker Gungerich · Hersbruck, DE
Andreas Blum · Reutlingen, DE
Uwe Weder · Freiburg im Breisgau, DE
Dierk Eichner · Hersbruck, DE
Robert Reiner · Neubiberg, DE
Gerhard Schraud · Mering, DE

Key dates

Filing date	May 7, 2001
Grant date	Oct 23, 2001
Priority date	—
Expiry date	May 7, 2021

Classification

Technology area (CPC H)Electricity
CPC primaryH04L25/062
WIPO fieldDigital communication
WIPO sectorElectrical engineering

Abstract

A method for demodulating a voltage which has been ASK modulated by changing the amplitude between a low level and a high level, in particular for use during contactless data transmission from a card reader/writer to a smart card, is described. The method is distinguished, in that, in an initialization phase, a first mean value is produced from the high voltage level and a stored partial voltage derived therefrom in order to detect a change to a low voltage level. The change to the low voltage level represents a start value and is detected by a subsequent comparison of the modulated voltage with the first mean value. In a subsequent demodulation phase, a second mean value is produced from the detected low voltage level and the high voltage level in order to demodulate the modulated voltage by comparing the modulated voltage with the second mean value.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.